Showing Field Of Static Charge

The following experiment to demonstrate the lines of force in a
static charge can be performed by anyone having a Whimshurst static
machine, such as the E. I. Co. type.

First buy or prepare some powdered glass by grinding up a few old
test tubes in an iron mortar and sifting thru a fine screen. Dry a
10 X 14 inch (size need not be exact) pine board thoroly and tack a
sheet of smooth drawing paper on it.

Prepare two pointed tinfoil strips A & A1 about 8 inches apart
on paper and connect with the two rods of the static machine. Draw
the balls on the machine far enough apart to prevent a discharge.
Drive off all moisture from the powdered glass by heating it and
sprinkle a light layer over paper.

When the static machine is started, tap the board very lightly and
the glass particles will form in curved lines, similar to the lines
formed by iron filings and a magnet.